addressing boiler water problems before they...
TRANSCRIPT
Addressing Boiler Water Problems Before They Start
Presented by Cleaver Brooks’ Steve Connor& Bill HookeNovember 30, 2016
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TODAY’S TOPICS
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• A review of the key take-a-ways from last month’s session
• What causes boiler water level fluctuations
• The dangerous side of carryover
• The causes and costs of pressure vessel failure & repair
• The causes and telltale signs of system upsets
• Step by step remedy process
• Choosing a qualified water treatment consultant
• Summary & questions
WHAT NEEDS TO BE REMOVED
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• Dissolved Minerals• Hard Scale Formers
• Calcium• Magnesium
• TDS• Calcium (Scale)• Magnesium (Scale)• Sulfate (Instability)• Iron (Scale)• Silica (Deposition)• Chloride (Instability)• Alkalinity (Foaming)
• Dissolved Gas• Free Oxygen (Corrosion)• Free Carbon Dioxide (Corrosion)
Waterside Scale
Waterside Corrosion
Foaming & Priming
Steam Outlet
Level Control/Sensor
Lose steam energy efficiencyDamage equipmentIncreases water hammer possibility
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WHAT NEEDS TO BE REMOVED
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• Dissolved Minerals• Hard Scale Formers
• Calcium• Magnesium
• TDS• Calcium (Scale)• Magnesium (Scale)• Sulfate (Instability)• Iron (Scale)• Silica (Deposition)• Chloride (Instability)• Alkalinity (Foaming)
• Dissolved Gas• Free Oxygen (Corrosion)• Free Carbon Dioxide (Corrosion)
Waterside Scale
Waterside Corrosion
WHAT NEEDS TO BE REMOVED
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• Dissolved Minerals• Hard Scale Formers
• Calcium• Magnesium
• TDS• Calcium (Scale)• Magnesium (Scale)• Sulfate (Instability)• Iron (Scale)• Silica (Deposition)• Chloride (Instability)• Alkalinity (Foaming)
• Dissolved Gas• Free Oxygen (Corrosion)• Free Carbon Dioxide (Corrosion)
Waterside Scale
Waterside Corrosion
1. Controlled the hardness and iron entering the boiler
2. Maintained the Plant specific Boiler chemistry:• Conductivity• Alkalinity • Sludge Conditioner
MINIMIZED POTENTIALFOR SCALE
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HOW CAN THISHAPPEN?
• Check the softener/ pretreatment• Especially at the end of cycle
• Confirm Testing of:• Feedwater: Hardness, iron• Boiler: Sludge conditioner,
Alkalinity, Conductivity
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1. Minimized the oxygen entering the boiler2. Maintained the oxygen scavenger in the boiler
• ALL THE TIME!
PREVENTED BOILERCORROSION
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Whenever the boiler is opened for inspection, check for oxygen pitting.
INSPECTION:GIVES REPORT CARD
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1. Maintain the oxygen scavenger in the boiler ALL THE TIME
2. Testing confirmed scavenger residual when running or idle
PREVENT BOILERCORROSION
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Minimized the carbon dioxide generated in boiler.
Reduced potential for H2CO3 Carbonic acid in the returning condensate water.
OUTSIDE THE BOILERPROTECTED CONDENSATE
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1. Employed proper condensate treatment
2. Tested and confirmed pH, iron, hardness and conductivity limits.
3. Kept logs of test results.
4. Test condensate from different areas of the plant, near and far.
PROTECTINGCONDENSATE
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Morpholine – protection near the steam generators
DEAE – Diethylaminoethanol –protection moderate distance from the boiler plant
Cyclohexyalmine – further protection.
Blends often used; testing several condensate sites help determine the best choice for each plant.
Different \ Amines:
PROTECTINGCONDENSATE
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Condensate corrosion with no corrective action results in…
Condensate loss, greater energy loss, more make up.
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CARRYOVER
Effects of priming, carryover and surging:• Boilers can shut down on low water• Water hammer can destroy piping –
Dangerous• Processes can be shut down• Product can be contaminates• Carryover causes more carryover
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Drop in Pressure• Sudden demand
259° F
Now, only 10 psi, and water boils at 239°
CARRYOVER -PRESSURE DROP
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Solution to potentially appalling potato peeling problem?
Three element feed/forward level system.
When the peeler is ready to call for steam, feedwaterpumps pre-emptively begin feeding feedwater to boiler prior to water level control signal.
CARRYOVER - EXAMPLEPROCESS DEMAND
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Overfeed of Treatment Chemicals High ConductivityHigh alkalinity
Sudden surge of suspended solidsHardness, chlorides
CARRYOVER -CHEMICALLY CAUSED
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Large feed of amine to the boiler Amine(s) vaporize at once
Automate feed.
CARRYOVER -OVERFEED OF AMINE
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Review: When does carryover occur?• Drop in Pressure
• Sudden demand?• What is happening?
• Check condensate for source• When equipment is cleaned• After ‘break’, early morning• Was chemistry in system
out of range?
Look for boiler chemistryin condensate, normally not far from the boiler room.
CARRYOVER SOLUTIONS
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Conductivity = 3500
Conductivity = 100
Contamination• Carryover from any cause will
contribute to more carryover
35 Cycles
CARRYOVER
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Conductivity = 3500
Conductivity = 700
Contamination• Carryover from any cause will
contribute to more carryover
5 Cycles
CARRYOVER
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Dump feedwater and/or contaminated condensate to slow carryover and replace tainted water with fresh make up.
• If oil is contaminant, maintain high OH alkalinity to tie up oil.
CARRYOVER -SOLUTIONS
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Make up water-pretreated
• Hardness• Conductivity• Water meter Track
Feedwater • Hardness 0• Conductivity Record• Alkalinity • Water meter Track • Iron 0
TESTINGIMPORTANCE OF LOG KEEPING
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Be on lookout for changes and upsetsThink “Cause & Effect”
TESTINGIMPORTANCE OF LOG KEEPING
Monitor and record boiler (minimum):• Conductivity (neutralized)• Alkalinity• Sludge conditioner (residual & inventory)• Oxygen Scavenger (residual & inventory)
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• Identify Control limits• Maintain Limits
• Make small adjustments to feed and bleed• Record adjustments• Record water use
TESTINGIMPORTANCE OF LOG KEEPING
The program manual by WT provider directs you to what to do.
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Logs help:• Show other operators
actions taken• Track chemical use, prevent
inventory mistakes• Document program
administration/protection
TESTINGIMPORTANCE OF LOG KEEPING
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Logging plant chemistry provides Better control.
NOTE: Insight into operating changes will Predict & Prevent greater problems
TESTINGIMPORTANCE OF LOG KEEPING
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Notice changes in boiler • Oil in sight glass• Milky look to boiler
• Hardness overwhelms Polymer• OH alkalinity drops
• Make up use change• Condensate / feedwater change
Notice Changes – Confirm, Retest, Explore
TESTINGIMPORTANCE OF LOG KEEPING
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TESTINGIMPORTANCE OF LOG KEEPING
1. Tests are done2. Trending is moving outside
of prescribed limits3. Notice this and…
MAKE AN ADJUSTMENT!!
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WET OR DRYBOILER LAY UP
Wet Lay Up
Maintain:• Sulfite – 100 ppm• P Alkalinity – 400 ppm
Warm boiler to circulate chemicals and insure protection.
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Wet• Quick Turnaround• Need to warm
regularly• Cascading bd• Circ. pump
• Maintain water level• Leaky header
Dry• Longer turn around to
fire• Header must be closed!!• Long term lay up• Seasonal lay up
WET OR DRYBOILER LAY UP
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How you will evaluate the supplier? Experience –
Do they have depth?How many years does the individual or company have in the field?Can they respond in timely fashion?Is the rep worthy of your business?
CHOOSING A WATERTREATMENT SUPPLIER
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How will you evaluate the supplier?Education –
Does rep have significant education in related field? Do they have experience and aptitude? Certified Water Technologist (CWT)?
CHOOSING A WATERTREATMENT SUPPLIER
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How will you evaluate the supplier?Expertise –
Does rep have knowledge of your system or problem?Can they share a similar application they’ve encountered?
CHOOSING A WATERTREATMENT SUPPLIER
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CHOOSING A WATERTREATMENT SUPPLIER
How will you evaluate the supplier?Costs –
Does the rep understand the cost for a barrel of chemical is unrelated to cost for competitor’s barrel of the ‘same’ stuff?
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Inspections
CHOOSING A WATERTREATMENT SUPPLIER
How will you evaluate the supplier?Costs –
Does the rep realize that cost of chemicals represents a small percentage of operating utility?
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CHOOSING A WATERTREATMENT SUPPLIER
How will you evaluate the supplier?Product Handling –
• Options for product handling?• Hands free?• Powder/liquid?• Solid?
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TODAY’S TAKE-A-WAYS
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• A sound water treatment program is one which uses both mechanical and chemicalmeans.
• Bouncing water line in the boiler can be both system and water composition induced.• Most often it is system related involving sudden pressure drops. • A three element feedwater system can help solve sink/swell problems in the boiler.• Sink/swell, foaming and priming can lead to carryover which can lead to water hammer.• Water hammer is NOT NORMAL! It MUST be remedied!!• Important to check for corrosion and scale and if evidence, check your log against that
of the water treatment professional you have engaged.• Regularly documenting The Chemical Log Book is essential for a reliable program.• Light scale in or on boiler tubes is no longer considered wise for boiler protection. • Look for evidence of boiler chemicals in the condensate. Could be sign of Carryover• Laying a boiler up Wet or Dry is largely dependent on the amount of time the boiler will
be off line.• The key factors to consider when choosing a reputable water treatment expert are
Education, Expertise and Cost.
Steve ConnorConsultant: Marketing & [email protected] 377- 6347
QUESTIONS?
Bill HookeWater Treatment ConsultantChemtex [email protected]
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